Makumbane Vhahangwele, Kroon Robin E, Yagoub Mubarak Y A, Erasmus Lucas J B, Coetsee E, Swart Hendrik C
Department of Physics, University of the Free State, Bloemfontein, 9300, South Africa.
Sci Rep. 2024 Aug 1;14(1):17758. doi: 10.1038/s41598-024-68367-x.
The structural, surface, and upconversion (UC) luminescence properties of YO:Ho,Yb films grown by pulsed laser deposition, for different numbers of laser pulses, were studied. The crystallinity, surface, and UC luminescence properties of the thin films were found to be highly dependent on the number of laser pulses. The X-ray powder diffraction analysis revealed that YO:Ho,Yb films were formed in a cubic structure phase with an Ia space group. The thicknesses of the films were estimated by using cross-sectional scanning electron microscopy, depth profiles using X-ray photoelectron spectroscopy (XPS), and the Swanepoel method. The high-resolution XPS was used to determine the chemical composition and oxidation states of the prepared films. The UC emissions were observed at 538, 550, 666, and 756 nm, assigned to the F → I, S → I, F → I, and S → I transitions of the Ho ions. The power dependence measurements confirmed the involvement of a two-photon process in the UC process. The color purity estimated from the Commission International de I'Eclairage coordinates confirmed strong green UC emission. The results suggested that the YO:Ho,Yb UC transparent films are good candidates for various applications, including solar cell applications.
研究了通过脉冲激光沉积生长的不同激光脉冲数的YO:Ho,Yb薄膜的结构、表面和上转换（UC）发光特性。发现薄膜的结晶度、表面和UC发光特性高度依赖于激光脉冲数。X射线粉末衍射分析表明，YO:Ho,Yb薄膜以具有Ia空间群的立方结构相形成。通过使用横截面扫描电子显微镜、X射线光电子能谱（XPS）深度剖析和Swanepoel方法来估计薄膜的厚度。使用高分辨率XPS来确定制备薄膜的化学成分和氧化态。在538、550、666和756nm处观察到UC发射，其归因于Ho离子的F→I、S→I、F→I和S→I跃迁。功率依赖性测量证实了双光子过程参与UC过程。根据国际照明委员会坐标估计的色纯度证实了强烈的绿色UC发射。结果表明，YO:Ho,Yb UC透明薄膜是包括太阳能电池应用在内的各种应用的良好候选材料。
